In healthy women, fezolinetant Cmax and AUC increased proportionally over a dosage range from 20 to 60 mg once daily (0.44 to 1.33 times the approved recommended dosage).
Steady-state plasma concentrations of fezolinetant were reached after two once daily doses, with minimal fezolinetant accumulation.
Absorption
The median (range) time to reach fezolinetant Cmax is 1.5 (1 to 4) hours in healthy women.
Effect of Food
No clinically significant differences in fezolinetant pharmacokinetics were observed following administration with a high‑calorie, high-fat meal containing approximately 1000 calories (500-600 calories from fat, 250 calories from carbohydrates, and 150 calories from protein).
Distribution
The mean apparent volume of distribution (Vz/F) of fezolinetant is 189 L. The plasma protein binding of fezolinetant is 51%. The blood-to-plasma ratio is 0.9.
Elimination
The effective half-life (t1/2) of fezolinetant is 9.6 hours in women with vasomotor symptoms. The apparent clearance at steady-state of fezolinetant is 10.8 L/h.
Metabolism
Fezolinetant is primarily metabolized by CYP1A2 and to a lesser extent by CYP2C9 and CYP2C19. A major metabolite of fezolinetant, ES259564, was identified in plasma. ES259564 is approximately 20-fold less potent than the parent. The metabolite-to-parent ratio ranges from 0.7 to 1.8.
Excretion
Following oral administration of fezolinetant, 76.9% of the dose was excreted in urine (1.1% unchanged) and 14.7% in feces (0.1% unchanged).
Specific Populations
There were no substantive differences in the pharmacokinetics of VEOZAH based on race and body weight (93 to 278 pounds).
Women with Renal Impairment
Following single-dose administration of 30 mg fezolinetant, there was no effect on VEOZAH exposure (Cmax and AUC) in women with mild (eGFR 60 to less than 90 mL/min/1.73 m2) to severe (eGFR 15 to less than 30 mL/min/1.73 m2) renal impairment. The AUC of ES259564 (a major metabolite of fezolinetant) in women with moderate (eGFR 30 to less than 60 mL/min/1.73 m2) and severe (eGFR 15 to less than 30 mL/min/1.73 m2) renal impairment increased by approximately 75% and 380%, respectively. VEOZAH has not been studied in individuals with end-stage renal disease (eGFR less than 15 mL/min/1.73 m2).
Women with Hepatic Impairment
Following single-dose administration of 30 mg fezolinetant in women with mild Child-Pugh Class A cirrhosis, the mean Cmax increased by 23% and AUCinf increased by 56%, relative to women with normal hepatic function. In women with moderate Child-Pugh Class B cirrhosis, the mean Cmax of fezolinetant decreased by 15% and AUCinf increased by 96%. The Cmax of ES259564 decreased in both mild and moderate cirrhosis while AUCinf and AUClast increased less than 15%. VEOZAH has not been studied in individuals with severe Child-Pugh Class C cirrhosis.
Drug Interaction Studies
Clinical Studies and Model-Informed Approaches
Strong CYP1A2 Inhibitors: Fezolinetant Cmax increased by 80% and AUC increased by 840% following concomitant use with fluvoxamine (strong CYP1A2 inhibitor).
Moderate CYP1A2 Inhibitors: Fezolinetant Cmax increased by 40% and AUC increased by 360% following concomitant use with mexiletine (moderate CYP1A2 inhibitor) 400 mg every 8 hours.
Weak CYP1A2 Inhibitors: Fezolinetant Cmax increased by 30% and AUC increased by 100% following concomitant use with cimetidine (weak CYP1A2 inhibitor) 300 mg every 6 hours.
No clinically significant differences in fezolinetant exposure were observed in smokers (moderate CYP1A2 inducer).
In Vitro Studies
Cytochrome P450 (CYP) Enzymes: Fezolinetant and ES259564 are not inhibitors of CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Fezolinetant and ES259564 are not inducers of CYP1A2, CYP2B6, and CYP3A4.
Transporter Systems
Fezolinetant is not a substrate nor an inhibitor of P-glycoprotein (P-gp). ES259564 is a substrate of P-gp, but not an inhibitor of P-gp.
Both fezolinetant and ES259564 are not a substrate of BCRP, OATP1B1, and OATP1B3. In addition, ES259564 is not a substrate of OAT1, OAT3, OCT2, MATE1, and MATE2-K.